A former Central Intelligence Agency director and ambassador to China, Vice President George H. W. Bush succeeded Reagan in January 1989. President Bush's one-term administration inherited a tentatively cooperative relationship with the Soviet Union, the moribund START I negotiations, and a well-funded research and development program for strategic missile defense. Gorbachev, meanwhile, had been proceeding with unprecedented reforms in the Soviet Union and its satellite states. As he cut the Soviet military by 500,000 men and reduced Red Army troop levels in Eastern Europe, public demonstrations demanding freedom from communist rule spread from the shipyards of Gdansk to the coffee shops of East Berlin. A totally unpredictable unraveling had begun. In November 1989 the Berlin Wall was literally dismantled by crowds of young people fed up with the economic and political sterility of the communist system. The destruction of the emblem of East-West division shook the Soviet Union to its core, but somehow in the midst of chaos Gorbachev managed to reach out to the new government in Washington. For its part, the Bush administration sharply slowed Reagan's very costly force buildup and began to reconfigure the planned missile defense architecture that had been created to support SDI. Eventually, the president would attempt to modify the ABM Treaty, but first he and Gorbachev sought to revitalize the START process, a casualty of the Reagan-Gorbachev contretemps over SDI. Meeting in Washington, D.C., in June 1990, Bush and Gorbachev initialed a trade pact and opened negotiations for deeper cuts in strategic weapons.
A year later, in July 1991, they met in Moscow to sign the START I treaty. The new accord reduced and limited total numbers of warheads rather than delivery systems. This was a breakthrough for arms control, although a cap of 4,900 ballistic-missile warheads does seem phantasmagorical. The approach had political appeal as a tool for both leaders to demonstrate to their constituents their seriousness about reducing the threat of nuclear war. It is equally true, however, that the dissolution of the Soviet Union and the Warsaw Pact within six months of each other made the enormous size of the U.S. nuclear arsenal a political and economic liability more than a security asset. American strategic planners began to calculate the level of weapons actually needed to ensure the security of the United States in a world order no longer defined by nuclear bipolarity.
START I was Gorbachev's diplomatic swan song. On the evening of 25 December 1991, the hammer and sickle was lowered from the Kremlin's flagstaff for the last time, and the Soviet Union ceased to be. Boris Yeltsin, who had been outmaneuvering Gorbachev for primacy within the Soviet Union, became president of the new Russian Federation. Bush preferred to work with the less volatile Gorbachev, but in a typically pedestrian aside he said, "You dance with who is on the dance floor." The American pragmatist and the Russian usurper contrived to sign the SALT II agreement just before Bush left office in January 1993. It reduced the total of nuclear warheads to between 3,000 and 3,500 for each side. All MIRVed missiles were to be eliminated by the year 2003.
No matter how comprehensive, Russian-American cooperation was no longer a sufficient guarantee of nuclear security, as both Yeltsin and Bush realized. In the last decade of the twentieth century, Russia and the United States suddenly encountered a new and unprecedented danger of attack by "rogue states" equipped with nuclear missiles. It was common knowledge that Iraq and Iran had used chemical weapons against one another during their eight-year war (1980–1988), and it had been estimated in 1990 that the Iraqis were "perhaps one year away from deploying a nuclear device." During the Gulf War of 1991, Iraq brazenly launched short-range Scud missiles to terrorize Saudis in Riyadh and Israelis in Tel Aviv, and American-designed Patriot missiles performed marginally as counters to the Scuds. Sub-sequent arms-elimination inspections by the United Nations exposed an extensive and sophisticated Iraqi network of nuclear, biological, and chemical weapons installations. Iraq and other so-called rogue states could no longer be discounted as insignificant to the international nuclear calculus. Something had to be done to ensure that the American homeland remained invulnerable to missile attack by minor powers possessing weapons of mass destruction.
President Bush reacted to the alarm with a new missile defense concept called Global Protection Against Limited Strikes. Bearing the friendly acronym GPALS, the innovation of 1991 showed that the proponents of Reagan's "Star Wars" had never really gone away. Like SDI before it, GPALS would take nuclear warfare into space, initially with space-based sensors but eventually to include actual missile interceptors in earth orbit. To allow testing and deployment of these new systems, the administration formally proposed changes to the 1972 ABM Treaty. Suddenly divested of its sacrosanct character, the treaty would remain under siege for the rest of the twentieth century and into the twenty-first.